Traditional analog photography created specific looks associated with the actual image reproduction technique. Over the years, people have become accustomed to these looks, and actually enjoy the “artifacts” of the system. One such artifact is image grain, especially for black and white photography. Grain is inherent to the analog photographic system, and is actually a visible artifact of the photosensitive capture molecules themselves. Despite the fact that grain is an artifact, it has a very distinctive look, and a look that many people wish to recreate in the digital photography world.
Simulation of image grain in the digital world is non-trivial, because digital photography has no film for any film grain to exist within. In digital cameras, the closest physical equivalents to film grain are the individual elements of the image sensor (e.g., a charge-coupled device (“CCD”) cell). Unfortunately, pixels from a digital image sensor are organized in straight lines. These straight line artifacts may irritate the viewer more than the randomly arranged film grains.
An alternative to relying on digital image sensors as the source of image graininess is to apply a film grain overlay, which adds film noise characteristics to the digital image. However, overlaying film grain often affects dark and bright tonal regions of the digital image. For instance, superimposed graininess often alters the depth of black in the image and is disturbingly visible (appearing artificial) in the brighter tonal region of the image. As a result, the graininess created by simply overlaying film grain on the digital image is often not as visually pleasing as the film grain produced by traditional photography.
Therefore, there is a need for tools that digitally recreate the effect of film grain which is as visually pleasing and as similar to the film grain produced by traditional analog photography as possible.